The Addams Family (movie version, though the TV series came first). Other films that would make good Hallowe'en costumes because they're famous, though not really "fashion": The Munsters (similarly, a TV show first), scI-fi (Barbarella, Star Trek, Star Wars, The Rocky Horror Picture Show), fantasy (Mary Poppins, any Disney animation), Rocky, Shaft, Tom Cruise in "Risky Business", Men in Black.
The members of the odd Addams Family are up to more macabre antics in this sequel. This time around husband and wife are celebrating the arrival of a baby boy. But siblings re none too happy about the new addition, and try their best to eliminate the infant. When nanny Debbie appears to keep the kids in line, her presence leads to an unexpected treacherous twist in which the whole family must stick and work together to get to the bottom of, stressing the importance of a strong family.